Abraham Lincoln had long regarded slavery as an evil. In a speech in Peoria, Illinois, in 1854, he declared that all national legislation should be framed on the principle that slavery was to be restricted and eventually abolished. He contended also that the principle of popular sovereignty was false, for slavery in the western territories was the concern not only of the local inhabitants but of the United States as a whole. This speech made him widely known throughout the growing West.

In 1858 Lincoln opposed Stephen A. Douglas for election to the U.S. Senate from Illinois. In the first paragraph of his opening campaign speech, on June 17, Lincoln struck the keynote of American history for the seven years to follow:

A house divided against itself cannot stand. I believe this government cannot endure permanently half slave and half free. I do not expect the Union to be dissolved -- I do not expect the house to fall -- but I do expect it will cease to be divided.

Lincoln and Douglas engaged in a series of seven debates in the ensuing months of 1858. Senator Douglas, known as the "Little Giant," had an enviable reputation as an orator, but he met his match in Lincoln, who eloquently challenged the concept of popular sovereignty as defined by Douglas and his allies. In the end, Douglas won the election by a small margin, but Lincoln had achieved stature as a national figure.

Sectional strife was growing ever more acute. On the night of October 16, 1859, John Brown, an antislavery fanatic who had captured and killed five proslavery settlers in Kansas three years before, led a band of followers in an attack on the federal arsenal at Harper's Ferry in what is now the state of West Virginia. Brown's goal was to use the weapons seized to lead a slave uprising. After two days of fighting, Brown and his surviving men were taken prisoner by a force of U.S. marines commanded by Colonel Robert E. Lee.

Alarm ran through the nation. For many Southerners, Brown's attempt confirmed their worst fears. Antislavery zealots, on the other hand, hailed Brown as a martyr to a great cause. Most Northerners repudiated his deed, seeing in it an assault on law and order. Brown was tried for conspiracy, treason and murder, and on December 2, 1859, he was hanged. To the end, he believed he had been an instrument in the hand of God.